d) Intestinal obstruction: The presence of generalized abdominal pain, absent bowel sounds, and X-ray findings of dilated small bowel and part of the transverse colon without fluid levels are highly suggestive of intestinal obstruction. Although the absence of fluid levels might seem unusual, it can occur early in the course of obstruction or if the obstruction is partial.

a) Pancreatitis: While pancreatitis can cause abdominal pain and elevated temperature, the X-ray findings of dilated bowel loops are not typical for pancreatitis alone. However, it's possible in severe cases or if there's associated ileus.
c) Bacterial colitis: This could cause abdominal pain and fever, but the X-ray findings of dilated small bowel and part of the transverse colon are more indicative of a mechanical issue like obstruction rather than an infectious colitis which might show thumbprinting or toxic megacolon in more severe cases.

b) Perforated peptic ulcer: Although the X-ray does not show free air under the diaphragm (which is a classic sign of perforation), a perforated viscus is a surgical emergency that can present with abdominal pain and fever. The absence of free air does not rule out a perforation, especially if it's contained or if the patient is not in the optimal position for the X-ray to detect free air.

Other rare causes could include ischemic bowel, which might present with similar symptoms but would typically have additional risk factors or findings suggestive of vascular compromise.
Certain inflammatory conditions like Crohn's disease could also cause similar X-ray findings, but the acute presentation and age of the patient make this less likely without a prior history of the disease.